Our invention concerns a new iron golf club which eliminates a bridge between blade and hosel of the head and juxtaposes blade and head thereby redistributing weight in the golf club head to increase mass available for momentum transfer to a golf ball. The hosel has a constant diameter through passage to the sole of the golf club head in which the club shaft is secured. In a developmental view of the sole of each club head, or in bottom view of each club head, the lower end of the hosel extending at an obtuse angle rearwardly from the heel end of the blade in the manner of a dog-leg. In a modified form of the invention, the sole end of the hosel is substantially squared relative to the longitudinal axis of the hosel forming a step in the sole, thereby reducing weight of metal of said hosel which is redistributed to the blade.
The iron golf club we have invented includes the following characteristics:
(1) An iron golf club head with a short, hollow hosel disposed at the heel end of the blade and formed from the same continuous piece of metal as an integral part completely lapping the heel end of the blade from top to bottom of the blade. There is substantially no bridge between blade and hosel and there is no bridge at all below the hosel. The hosel extends from a level above the top of the blade down to the sole of the club head. The hosel has through passage or bore of constant diameter extending from the top of the hosel down through the sole. A golf club shaft is fixedly secured in the hosel and extends completely to the sole.
(2) An iron golf club head whose sole is wide enough at the heel to permit a three-eighths inch diameter hole to be drilled completely though the hosel and heel to accept full shaft penetration completely to the sole of the club head.
(3) An iron golf club head which provides for redistributing the mass from the portion of the hosel which has been eliminated by use of a short hosel and from the drilled hole and substantial elimination of a bridge between blade and hosel to that portion of the club head which contributes to the transfer of momentum to the golf ball. The golf clubs with the weight thus redistributed will have a minimum of fifteen percent more mass available for momentum transfer when compared to conventional iron golf clubs with the same loft. Note should be taken that when a bridge is substantially eliminated between blade and hosel, the weight otherwise devoted to the bridge is free to be relocated to a blade area.
(4) An iron golf club head with almost ideal toe to heel weight distribution so that it provides maximum torque resistance when golf ball contact is made at a point removed from the center of percussion, by having a greater lateral moment of inertia.
(5) An iron golf club with improved "feel" resulting from a concentration of the club head mass and from the fact that the shaft extends completely to the sole of the club head.
(6) An iron golf club head with a short hosel having a straight generally even diameter opening through to the club head sole and the club shaft extending completely to the sole of the club head and the parts of the head having such relationships that in a developmental view of the sole of the club head, or in a bottom view of the club head, the lower end of the hosel extends from the heel end of the blade at an obtuse angle forwardly from the heel end of the blade in the manner of a dog-leg.
(7) In a modified form of the invention, the sole end of the hosel is substantially squared relative to the longitudinal axis of the hosel forming a step in the sole, thereby reducing weight of the metal of the hosel which is distributed to the blade.
It is an objective of our invention to design club heads having the foregoing characteristics.
The purpose of these design features is to improve the performance characteristics of the iron golf club. Due to the concentration of the weight resulting from the transfer of mass from the hosel and bridge to the blade itself, the golfer will be more aware of the club head at all points during the swing. This should lead directly to improved consistency and effectiveness in returning the club head to the ball on the forward swing.
As a result of the foregoing features (other than the step) as much as approximately thirty seven grams (1.3 ounces) is free to be redistributed from the hosel and bridge to the blade. This can represent nearly twenty percent of the total club head weight for a 2-iron and over fifteen percent of the total club head weight for both the pitching wedge and the sand wedge. This improvement is accomplished without changing the overall weight of the golf club or of the club head (hosel plus striking blade).
All golf clubs are composed of three parts, the grip, the shaft, and the club head. Only the club head contributes to the actual flight of the ball. The shaft and the grip are important in that they assist the player in bringing the head of the golf club to the ball in an effective manner, much as the handle of the hammer or axe brings the working part of the tool to the work itself.
Our analysis of the iron club head reveals that the conventional club head is really composed of three parts, two of which are necessary:
(1) The blade, which is used to strike the golf ball.
(2) The hosel which provides the means for attaching the club head to the shaft. The hosel can be considered to be a necessary evil since other than holding the shaft it adds weight without contributing to that part of the club which imparts momentum to the golf ball. A more effective location for the hosel would be at a point near the center of percussion of the club head, a position which would result in the golf club being classified as "center-shafted". However, the rules of golf do not permit this configuration, except in the case of putters. For golf clubs, other than putters, the rules state, ". . . the shaft and the neck or socket must remain in line with the heel, or with a point to the left or right of the heel, when the club is viewed in the address position."
(3) A third part hitherto has been considered to be necessary in iron club heads, namely a bridge connecting the blade and the hosel. We have reached the conclusion that a bridge can be substantially eliminated in an iron club head, i.e., a short hosel can be formed directly at the end of the blade, the hosel socket can be formed as a constant diameter passage extending through the sole of the club head, and the shaft can be fixedly secured in that passage and extend completely to the sole. There is no bridge at all below the hosel whereas in the past in irons there always has been a bridge below the hosel. The hosel can be further shortened by squaring its lower end and by suitably redistributing to the blade this extra saved weight.
Conventional golf club iron heads have 20 to 25 percent of their weight in the hosel and the bridge. In order to compensate for this, manufacturers of irons shape the blade so that it is wider at the toe than at the heel. This helps to move the center of percussion (sweet spot) somewhat further from the hosel toward the center of the blade. For a golf club the center of percussion is that point on the club face at which the ball may be squarely struck without creating torque or a loss in momentum transfer. Some manufacturers carry this a step further and "toe-weight" the iron club head at the back. But even toe-weighted iron clubs may still have as much as 20 percent of the head weight in the hosel and bridge area.
It is an objective of our invention to reduce material in the hosel-bridge area of an iron golf club head and to redistribute the weight to the blade which contributes to the transfer of momentum to the golf ball.
More specifically, our design concept provides for removing about 1.3 ounces of material from within one-half inch of the heel of the iron club head on line with the axis of the shaft. Considering that the weight of the iron heads will vary from 8.5 ounces for a 2-iron to 10.5 ounces for a wedge, the material available for transfer, or redistribution, represents 15 to 20 percent of the total head weight and it is an objective of our invention to redistribute weight in the head in an amount of at least fifteen percent of the total head weight.
The "shaft-over-hosel" arrangement used by some manufacturers does not really save weight for redistribution to the striking area of the golf club, even though it may appear that way to the untrained eye. What appears to be a shorter and lighter hosel has a solid cylindrical section hidden inside and covered by the lower section of the shaft.
Golf clubs employing the conventional shaft/hosel arrangement have the shaft attached to only the upper one to one and one-half inches of the hosel which has been cast or bored to accept either a tapered or parallel tip of a shaft. This is a waste of material (as to the bridge between the hosel per se and the club blade) because, in addition to providing useless weight in that location, it adds aerodynamic drag near the point where the velocity is the greatest. Since parasitic drag of this nature is proportional to the square of the velocity, the effect is significant. It is an objective of our invention to reduce height and weight in the area of the hosel.
In our new design, the amount of hosel remaining on the golf club can be as low as about one inch long, which is enough for a satisfactory union with the shaft. More importantly, the part of the hosel and bridge that has been eliminated is that portion which was furthest from the center of the blade of the club head and has the most undesirable effect on the location of the center of percussion. This is readily apparent when one realizes that the standard lie angles for irons vary from 57 degrees to 64 degrees with an average of 60 degrees. This means that the hosel mass is tilted 30 degrees away from the toe of the iron golf club head. Yet another benefit derived from moving the center of percussion toward the toe is that the sweet spot is now located further from the hosel and this lessens the probability of experiencing the dreaded shanked golf shot where the ball is deflected sharply to the side as a result of inadvertently contacting the hosel.
Our invention will be best understood, together with additional advantages and objectives thereof, when read with reference to the drawings.